(296) Missingness as a social determinant: data gaps undermine aspirin eligibility for preeclampsia risk reduction

Low-dose aspirin (LDA) is recommended for pregnant persons at elevated risk for preeclampsia. Eligibility depends on availability of clinical and social risk factor data. Income, a moderate risk factor per USPSTF, is frequently missing and may contribute to under identification. We evaluated whether missing income data was associated with differential LDA eligibility across racial and ethnic groups and its impact on preeclampsia outcomes.

Study Design:

A secondary analysis of the nuMoM2b study, a prospective cohort of nulliparous individuals with singleton pregnancies. We included subjects with available preeclampsia outcome data. USPSTF criteria were applied to determine LDA eligibility, classifying participants eligible if they had ≥1 high-risk or ≥2 moderate risk factors (all met nulliparity; Black race was excluded to allow subgroup analysis). We quantified how many moderate risk factors were present, whether income data were missing, and how missingness varied by sociodemographic characteristics. Last, we examined how LDA eligibility changed based on the presence of income data.

Results:

8,775 participants were included. 4,729 (54%) met LDA criteria, with 4,331 (92%) qualifying through moderate-risk factors alone. Of these, 3,186 (74%) had only one additional moderate-risk factor beyond nulliparity, most commonly income (Fig 1).

Income data were disproportionately missing among participants who were younger, Black, Hispanic, government-insured, or had lower education levels and was associated with lower LDA eligibility (Table 1). Among participants who developed preeclampsia but were not identified for prophylaxis, income data were missing in 84% of Black and 67% of Hispanic versus 12% of White individuals (Fig 1).

Conclusion:

Missingness itself may function as a social determinant of health, undermining equitable identification of patients who qualify for LDA prophylaxis and disproportionately excluding those already at elevated risk. Addressing structural missingness and improving routine collection of social risk factors are essential steps to reduce disparities in preeclampsia prevention.